If you love the dress from China more, then I'd go for that!
I ordered a dress from China once through Ebay, and wouldn't have got anything similar to that on the High Street in this country for the small amount I paid! Normally, these sellers have lots of info about their sizes in the 'item description' so just check that tallies with you. And any questions about the sizing, I'm sure they'll be able to help you.
The only slight problem I had was that I have long arms. The dress was meant to be long sleeve, but it ended up practically being three-quarter sleeve! It was on my elbow practically. This wasn't a problem - I can only assume that their target market have significantly smaller arms

So possibly something to bear in mind if it's a long sleeved dress you are looking at on Ebay
I too also like to try on anything before I buy it, but sometimes, with the styles and prices that you see from these sellers in China, you just have to risk it
Can't wait to see the pictures!
ETA - LOVE those dresses above!!!!!!!